A work machine including a working unit is known. For example, when the work machine is an excavator, the working unit has a bucket, an arm, and a boom. A hydraulic cylinder is used as an actuator for operating the working unit. A hydraulic pump that discharges operating oil is used as a drive source of the hydraulic cylinder. A work machine including a plurality of hydraulic pumps for driving the hydraulic cylinder is known. Patent Literature 1 discloses a hydraulic circuit including a merging valve that selectively merges or splits the operating oil discharged from a first hydraulic pump and the operating oil discharged from a second hydraulic pump.